1. Field of the Invention
The invention relates to a digital tachograph and to a method for signing vehicle-relevant data.
2. Related Art
DE 197 38 631 A1 discloses a method and an arrangement for monitoring motor vehicles, wherein the motor vehicles contain a tachograph for ascertaining and storing a piece of journey-specific information and the stored pieces of information are checked, with the piece of information from an electronic tachograph being transmitted to a remote query module in the motor vehicle, the piece of information being transmitted to an external query appliance and the piece of information being conditioned and presented in the query appliance. The remote query module is intended to send only following a correct request by a query appliance.
A method and an appliance for documenting vehicle data are disclosed by DE 197 10 333 A1. This document proposes the vehicle data is collected by a data memory unit installed in the vehicle, conditioned and stored in a storage medium up until external processing. It is intended to be possible to store data on a chip card in encrypted form and to decrypt the data using an evaluation program.
DE 100 32 301 A1 discloses a travel data acquisition, travel data transmission and travel data output system for use in a public local or long-distance transport network with a travel data generator, a travel data transmitter and a travel data receiver. The travel data generator is intended to automatically capture and encode data from a respective vehicle, and the travel data transmitter is intended to transmit the travel data captured and encoded by the travel data generator.
According to European community regulations 2135/98, 1360/2002 and 3821/85, a digital tachograph needs to be shown for all commercial vehicles with a vehicle weight greater than 3.5 t and for certain buses on the registration date within EU member states from May 1, 2006 onward. The aim of digital tachographs is to combat simple opportunities for misuse in order to be able to undertake protected and confidential storage of these travel data on a personal driver card and in a mass memory in the appliance through the use of digital data processing. If necessary, the travel data can be printed. Digital tachographs need to be checked for functionality, and calibrated, at least every two years.
At present, it is possible for vehicle-relevant data that are recorded and ascertained by a digital tachograph, such as driving-period, to be manipulated, the manipulation not being evident to outside third parties, such as regulatory authorities. For the regulatory authorities, such as the police, this means that the vehicle-relevant data to be checked for a vehicle that is to be checked are unreliable, since it is not possible to check whether they are authentic and/or have not been manipulated.
The recorded vehicle-relevant data might have been changed, with it not being clearly evident what prompted the change, since it is not possible to distinguish whether mischievous manipulation, or incorrect information produced by transmission errors is involved. As a result, trustworthiness for rating the vehicle-relevant data can be classified as low. Current “trust-based” solutions for the capture of vehicle-relevant data can be regarded as suspect for a check by the regulatory authorities. The existing legal regulations that identify the data attributes of the vehicle-relevant data that need to be captured and must not be changed provide no guidelines with regard to reliability against manipulation and hence no Q factor or quality indicator about the reliability of the data attributes of the vehicle-relevant data per se that need to be captured. Therein lies the opportunity to make unrecognizable modifications to the vehicle-relevant data. In the existing legal guidelines, the captured vehicle-relevant data are totally unprotected and can be regarded as not forgery-proof.